Glossary
Karat
A measure of gold purity expressed in 24ths.
Definition
One karat represents 1/24 pure gold by mass. 24 karat gold is 99.9% pure; 22 karat is 91.7%; 18 karat is 75%. Karat is the retail-facing measure; the trade equivalent, fineness, expresses the same information in parts per thousand.